Guiding pipe camera (before the removal
As announced, TEPCO has inserted a cleaner robot onto the gangway in the Reactor 2 containment enclosure. It is equipped with a snowplow at the front, two cameras and a jet of pressurized water.
The robot was able to clean only one meter instead of the 5 expected. According to the Japanese document put online by TEPCO, in some places deposits were more adherent than expected, which slowed down the robot’s progress.
There are areas where the robot could not move forward. There are up to 2 cm of deposits that can be insulation and paint that have melted before sticking to the bridge. On a first attempt, the water pump did not work.
After two hours of activity, the cameras became obscured and the robot was quickly removed. TEPCO believes this is due to extremely high radiation levels.
The camera can only withstand a cumulative dose of about 1000 Sv. The analysis of the images gives an approximate dose rate of 650 Sv / h. This is even more than the recorded dose few days ago (530 Sv / h).
The company is reluctant to send the scorpion measuring robot because it could only take data for two hours.
It is not under the reactor vessel that the dose rates are the highest and TEPCO does not understand why.
TEPCo has released a new series of photos and a video. The video shows the magnitude and the difficulty of the task expected for this small robot.
TEPCO issued a press release in English, accompanied by the same photos and video and the technical note.